This invention relates to compositions useful as catalysts for vapor phase substitution chlorination of partially chlorinated organic materials by action of chlorine, or hydrogen chloride, and elemental oxygen in vapor phase at elevated temperature.
Such catalyzed reactions are broadly known. Illustrative is U.S. Pat. No. 3,210,431 of Oct. 5, 1965 to W. F. Engel. This patent discloses the substitution chlorination of saturated aliphatic and cycloaliphatic hydrocarbons and alkenes and aromatic hydrocarbons by reacting them with hydrogen chloride and oxygen or oxygen-containing gases in the presence of catalysts; for example, chlorides of copper and rare earth metals supported on silica gel, preferably; or on pumice. Copper content is generally 1 to 20% by weight. Temperatures disclosed in the patent are in the range from 100.degree. to 650.degree. C. According to that invention, the catalyst composition contains in addition to cupric chloride, the chlorides of one or more rare earth metals and one or more alkali metals. The patent states that by use thereof, relatively low temperatures, for example, 100.degree.-300.degree. C. can be employed. The advantages recited are that the copper chloride hardly or not at all volatilizes and there is hardly any corrosion; moreover, chlorinations of, in particular, alkenes proceed with high selectivity and the process can be carried out in a fluidized catalyst bed. The specific working examples show only ethylene as the hydrocarbon and only addition chlorination, not substitution chlorination.
Also known in the prior art is the formation of so-called intercalated compositions wherein various metal chlorides are heated at temperatures such as 100.degree. to 400.degree. C. with crystalline boron nitride, whereby a composition is formed in which the metal chloride is held by some such means as electronic interaction or coordination of cations within the layers of boron nitride crystals. (R. C. Croft, Australian Journal of Chemistry, volume 9 of 1956, pages 206-211.) Using specifically cuprous chloride at 400.degree. C. the percent of CuCl found in the boron nitride after washing was 5%, i.e. about 3.2% of copper.